With New Jersey Democratic gubernatorial nominee Phil Murphy so far ahead in the polls, some voters may figure there’s no point in casting a ballot Tuesday. But there is a very important reason to turn out in high numbers.

Lt. Gov. Kim Guadagno, the Republican nominee, has run a disgusting television ad that seizes on ethnic fear and hatred to reach a particular kind of voter. Because New Jersey is one of the nation’s most diverse and well-educated states, she went straight to the sewer to get maximum attention.

Guadagno’s ad tries to link Murphy to an “illegal alien and child rapist” who murdered three students in Newark a decade ago. She twisted Murphy’s words of support for “sanctuary” cities and states to argue that he had the backs of “deranged murderers” who would kill our kids. It is a flat-out lie, but it stokes up those who are open to hating anyone who is different.

But she forgets that New Jersey is all about difference. Many of the more than five million residents of European descent still identify with their ancestors from Italy, Ireland, Germany, Poland, and Portugal. A full range of Latinos, from Cuba to the Dominican Republic, and African Americans who trace their ancestry from West Africa to the West Indies are included among the state’s 8.9 million residents.

These New Jerseyans proudly pass down their families’ immigrant stories to the next generation. Meanwhile, most new immigrants to the state come from India and China. When you hear a language other than English in New Jersey, it’s usually Spanish, Portuguese, Polish, or Gujarati, an Indian tongue. Doesn’t matter: For the most part, people get along.

That’s not to say New Jersey is idyllic. Consider former Bordentown Township Police Chief Frank M. Nucera Jr., who has been charged with hate crimes after allegedly saying he wanted to kill African Americans, slamming a handcuffed black man into a door jamb, and using dogs to harass black people at high school basketball games.

Growing public acceptance of hatred seems to be occurring in this country. It elected a president who during his campaign derided Mexicans and an Indiana judge with a Hispanic surname. President Trump later described some racists and neo-Nazis demonstrating in Virginia as “very fine people.”

Such comments are symptoms of a disease that sickens democracy and Guadagno’s ad has made her a malicious carrier. But New Jersey voters get the last word.

Every voter unnerved by Guadagno’s smear on all immigrants should speak up at the polls. On Election Day, Jamaicans, Koreans, Puerto Ricans, Italians, Syrians, Armenians, Germans, and all the other ingredients in New Jersey’s melting pot should shove racist politics aside.

The election is to choose the next governor of New Jersey. But in doing that, voters can also make a strong comment about the kind of people who live in their state.

If voters who agree that Guadagno’s TV commercials are out of line choose to write in the name of someone not even on the ballot, that’s understandable. The point is to reject putrid politics that tries to turn neighbor against neighbor.